Anonymous wrote:No grazing and feed them separately.
Grazing can only be allowed for pets with good portion control.
This. Plus, give the obese cat only wet food and choose one with little to no ***carbs***, vs no grain. "No grain" foods still contain a whole bunch of potatoes, peas, carrots, etc. in most (not all) brands.
I like Weruva for my teetering-on-obese pet. He's a fatty bc he can't exercise due to injury. Your geriatric cat has a similar equation going on, so every calorie counts.
Ditch the grazing!!! And try to give up the low cost and convenience of dry if at all possible.